Management of patients with small pancreatic neuroendocrine tumors from a biomarker and surgical perspective

: Pancreatic neuroendocrine tumors (PanNETs) have an age-adjusted incidence of 1.5 per 100,000 people, with a notable rise in the incidence of small (≤ 2 cm) non-functional (NF-PanNETs) in recent decades. While surgery is traditionally the preferred treatment for localized NF-PanNETs, active surveillance is now an accepted management strategy for tumors smaller than 2 cm due to their relatively benign behavior. However, this approach has not yet been fully integrated into routine clinical practice. There is considerable histopathological heterogeneity observed in NF-PanNETs which results in significant variability in clinical presentation, behavior and treatment outcomes. Hence, tumor size alone does not provide sufficient certainty regarding a benign clinical course for decision-making. Although studies advocate for incorporating WHO grade into clinical prognostic assessments, also this marker has limitations. Several established tissue-based markers, such as ATRX and DAXX alterations, alternative lengthening of telomeres (ALT), and copy number variations can be used for PanNET subtyping and correlate with metastatic risk. Combining these markers with traditional histopathological parameters may yield a more comprehensive and accurate prognostic assessment. This review discusses advantages and limitations of current prognostication methods for small NF-PanNETs and highlights recently established prognostic markers, along with the requirements for their implementation into routine clinical practice. It also proposes practical solutions to address the challenges associated with an immediate integration of these biomarkers into routine care.